1. Field of the Invention
The present invention relates to an electric vehicle, such as an in-wheel motor vehicle, that is equipped with motor(s) to drive wheels and that may be battery-powered or fuel cell-powered.
2. Description of Related Art
An electric vehicle may experience malfunctions of a motor serving as a drive for the vehicle and/or malfunctions of a control system that controls the motor. This can significantly affect the travel performance or travel safety.
An electric vehicle may include a drive system which may be in the form of an in-wheel motor drive system. The components of an in-wheel motor drive system may include a wheel bearing, a reducer and a motor. Reliability of a motor, a wheel bearing and a reducer is an urgent concern for such an in-wheel motor drive system which, due to its smaller size, involves rapid rotation of the motor, and etc.
In the past, in the attempt to ensure such reliability, an in-wheel motor drive system has been proposed in which the temperature of components such as a wheel bearing, a reducer and a motor may be measured and monitored for overload, with features to limit a drive current in/to the motor or a rotational frequency of the motor according to the temperature measurements (see the Patent Document 1 listed below).    [Patent Document 1] JP Laid-open Patent Publication No. 2008-168790